1. Field of the Invention
This invention relates to suspension systems, and more particularly, to suspension systems for vehicle mounted beds.
2. Description of the Prior Art
Automobiles include highly sophisticated suspension systems which do an excellent job of isolating the passenger compartment from road induced shocks. The cab of a deisel powered truck, on the other hand, is essentially rigidly coupled to the truck frame and directly transmits to individuals in the cab all fore-and-aft and vertical excursions which are produced by irregularities and undulations in the road surface. With the escalating cost of trucks and trailer rigs, it is becoming increasingly important to maximize the utilization of these vehicles. In order to do so a pair of drivers is typically assigned to a truck so that the truck can be driven continuously for long periods of time to reach a remote destination. While one driver performs his driving duties, the other driver can be sleeping on a mattress attached to a horizontally oriented deck within the truck cab. Due to the direct coupling of the cab to the truck frame, it is highly important that some sort of an isolation means or suspension system be positioned between the mattress and the horizontally oriented deck of the vehicle to reduce the amplitude of the fore-and-aft and vertical pitching movements of the cab.
Various systems have been proposed in the past to accomplish this purpose. U.S. Pat. No. 3,760,436 (Zach) discloses a mattress suspension system which includes a horizontal mattress tray which is coupled to the system by a group of four vertically oriented straps. These straps allow the tray to swing in a fore-and-aft direction in order to decouple the mattress from fore-and-aft excursions of the truck cab. This device also includes an air spring biased scissor linkage to dampen the up and down excursions of the cab. The primary disadvantage of the Zach apparatus is that it requires a fairly substantial volume of the sleeping compartment of the truck cab and may unduly crowd a truck driver of physically large size. The scissor linkage and the air spring occupy a significant vertical distance and the vertically extending tray support bars coupled to each end of the suspension system are by design required to extend above the floor of the tray in order to permit a pendulum-like swing of the tray. This vertical extension of the ends of the suspension system reduces the total available length of the mattress which may be inserted within the very confined sleeping area of the truck cab.
A number of other suspension systems which are mechanically highly complicated and which only damp vertically oriented excursions of the truck cab are disclosed in the following U.S. Pat. Nos. 3,299,447 (Dome), 3,371,359 (Dome), 3,067,437 (Campbell), 3,882,558 (Christensen). None of these devices provide any means for decoupling or damping the fore-and-aft excursions of the truck cab.
Other less relevant prior art suspension systems are disclosed in the following U.S. Pat. Nos. 1,664,129 (Pallenberg) and 3,902,205 (Bell).